Flue gas denitration ammonia injection mixing device
Patent Information
- Application Number
- CN202522381096.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-10
- Publication Date
- 2026-10-23
- Estimated Expiration
- 2035-11-10
AI Technical Summary
[0003]现有喷氨装置存在诸多不足：一方面，传统固定喷氨格栅采用直孔喷射方式，氨雾仅能覆盖局部区域，烟道边缘与中心的氨浓度相对标准偏差常超过 20%，易导致脱硝效率波动、氨逃逸率居高不下；另一方面，部分依赖电机驱动或氨液反作用力的旋转喷氨装置，额外增加了系统能耗，同时受氨压稳定性限制，在低负荷工况下易出现旋转失稳问题
[0010]完全依赖烟气自身动能驱动旋转，无需外源动力，适配全负荷工况，实现节能降耗；通过高效捕获烟气自身动能驱动导流板旋转，进而带动喷氨喷嘴同步旋转，使氨空混合气形成大扩散角的螺旋射流，实现氨空混合气螺旋喷射与烟气全域均匀混合，有助于提升脱硝效率、降低氨逃逸率。通过多组矩阵式布局可灵活适配大截面脱硝烟道，适用于各类SCR 脱硝场景，对既有烟道改造兼容性好。
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Figure CN224877719U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of flue gas purification technology, and in particular to a flue gas denitrification and ammonia injection mixing device. Background Technology
[0002] In selective catalytic reduction (SCR) denitrification processes, the uniformity of the ammonia-air mixture with the flue gas is a core factor in ensuring denitrification efficiency and controlling ammonia slip rate, directly affecting the environmental compliance and operational economics of heavily polluting industries such as thermal power plants, industrial boilers, and waste incineration plants. With regulations such as the "Emission Standard of Air Pollutants for Thermal Power Plants" (GB 13223-2011) further tightening regulations on nitrogen oxides (NOx)... x With the further tightening of emission limits (requiring ≤30mg / m³ in some areas) and strict control over ammonia slip rate, the industry has placed higher demands on the precision and stability of ammonia injection mixing systems.
[0003] Existing ammonia injection devices have several shortcomings: Firstly, traditional fixed ammonia injection grids use a straight-hole injection method, meaning ammonia mist can only cover a localized area. The relative standard deviation of ammonia concentration between the flue edge and the center often exceeds 20%, easily leading to fluctuations in denitrification efficiency and persistently high ammonia escape rates. Secondly, some rotary ammonia injection devices, which rely on motor drive or the reaction force of liquid ammonia, increase system energy consumption and are prone to rotational instability under low-load conditions due to limitations in ammonia pressure stability. Therefore, there is an urgent need to develop a method that requires no external power source and utilizes the kinetic energy of the flue gas itself to achieve stable rotation, thereby meeting the requirement for uniform ammonia mist mixing in large-section denitrification flues. Summary of the Invention
[0004] Therefore, this utility model aims to provide a flue gas denitrification ammonia injection mixing device that does not rely on external power. It can capture the kinetic energy of the flue gas itself to drive the ammonia-air mixture to form a spiral injection, achieving uniform mixing with the flue gas throughout its entire range, ultimately achieving the technical goals of improving denitrification efficiency and reducing ammonia slip rate. To achieve the above objectives, this utility model provides the following technical solution:
[0005] A flue gas denitrification ammonia injection mixing device, characterized in that it includes a nested tube assembly, a flue gas driving assembly, a spherical ammonia injection assembly, and a rotary bearing assembly. The nested tube assembly includes an inner tube (1) and an outer tube (2), with the outer tube (2) sleeved on the outside of the inner tube (1); the flue gas driving assembly includes a plurality of guide plates (3) evenly distributed along the circumference of the outer tube (2); the spherical ammonia injection assembly includes a spherical nozzle (4) rigidly connected to the upper part of the outer tube (2), with the spherical nozzle (4) having 4 to 6 inclined spray holes (5).
[0006] The center lines of the inner tube (1), outer tube (2) and spherical nozzle (4) are located on the same vertical line. The inner tube (1) and outer tube (2) are connected and rotated through the bearing (6). The outer tube (2) and spherical nozzle (4) are rigidly connected and rotate synchronously.
[0007] The guide plates (3) are evenly distributed around the outer tube (2) in a quantity of 3 to 6, and are at an angle of 15° to 25° with the vertical flue gas flow direction and have the same rotation direction. The guide plates (3) can be rectangular, circular, or airfoil-shaped, etc., and convert the flue gas flow power into the rotation power of the device.
[0008] The spherical nozzle (4) has 4 to 6 inclined nozzles (5), the nozzles (5) and the radial direction of the spherical nozzle (4) are at an angle of 20° to 30°, and the nozzle diameter is 1.5 to 2 mm.
[0009] The beneficial effects of this utility model are as follows:
[0010] Driven entirely by the kinetic energy of the flue gas itself, it requires no external power source, adapts to all load conditions, and achieves energy saving and consumption reduction. By efficiently capturing the kinetic energy of the flue gas to drive the rotation of the guide plate, which in turn drives the ammonia injection nozzle to rotate synchronously, the ammonia-air mixture forms a spiral jet with a large diffusion angle. This achieves spiral injection of the ammonia-air mixture and uniform mixing of the flue gas throughout the entire area, which helps to improve denitrification efficiency and reduce ammonia slip rate. Through multiple sets of matrix layouts, it can be flexibly adapted to large-section denitrification flue ducts, is suitable for various SCR denitrification scenarios, and has good compatibility with the retrofitting of existing flue ducts. Attached Figure Description
[0011] Figure 1 This is a schematic diagram of a flue gas denitrification ammonia injection mixing device provided by this utility model.
[0012] Figure 2 This is a schematic diagram of the spherical ammonia injection component structure of a flue gas denitrification ammonia injection mixing device provided by this utility model.
[0013] Figure 3 This is a schematic diagram of the system structure of a flue gas denitrification ammonia injection mixing device provided by this utility model.
[0014] Figure 4 This is a schematic diagram showing the location and installation of a flue gas denitrification ammonia injection mixing device provided by this utility model in a denitrification system.
[0015] Explanation of reference numerals in the attached diagram: 1. Inner tube; 2. Outer tube; 3. Guide plate; 4. Spherical nozzle; 5. Nozzle; 6. Bearing. Detailed Implementation
[0016] The present invention will be further described below with reference to the accompanying drawings.
[0017] This embodiment provides a flue gas denitrification ammonia injection mixing device for use in flue gas denitrification (SCR) systems of coal-fired power plants or industrial boilers.
[0018] In this embodiment, the flue gas denitrification ammonia injection mixing device is installed in the vertical flue of the SCR reactor. Its main function is to fully and uniformly mix the injected ammonia (NH3) with the nitrogen oxides (NOx) in the flue gas before they enter the catalyst layer, so as to improve the denitrification efficiency, reduce ammonia escape, and prevent the formation of ammonium bisulfate.
[0019] like Figure 1 This is a simplified diagram of a flue gas denitrification ammonia injection mixing device according to this utility model, wherein: 1, inner pipe; 2, outer pipe; 3, guide plate; 4, spherical nozzle; 5, spray hole; 6, bearing.
[0020] Reference Figure 1 The flue gas denitrification ammonia injection mixing device consists of a nested tube assembly, a flue gas driving assembly, a spherical ammonia injection assembly, and a rotating bearing assembly. The axial kinetic energy of the rising flue gas in the vertical flue drives the guide plate to rotate, which in turn drives the nozzles to rotate synchronously. This achieves uniform mixing of the ammonia-air mixture with the rotating, rising flue gas over the entire area, enhancing the mixing process, resulting in more uniform ammonia distribution, shortening the distance required to achieve ammonia homogenization, improving denitrification efficiency, and reducing ammonia escape rate.
[0021] Specifically, refer to Figure 1 and Figure 2 The center lines of the inner tube (1), outer tube (2) and spherical nozzle (4) are located on the same vertical line. The inner tube (1) and outer tube (2) are connected and rotated through the bearing (6). The outer tube (2) and spherical nozzle (4) are rigidly connected and rotate synchronously.
[0022] Reference Figure 1 The guide plates (3) are evenly distributed around the outer pipe (2), with a quantity of 3 to 6. They are at an angle of 15° to 25° with the vertical flue gas flow direction and rotate in the same direction. The guide plates (3) are rectangular and convert the flue gas flow power into the rotation power of the device.
[0023] Reference Figure 2 The spherical nozzle (4) has 4 to 6 inclined nozzles (5), the angle between the inclined nozzles (5) and the radial direction of the spherical nozzle (4) is 20° to 30°, and the nozzle diameter is 1.5 to 2 mm.
[0024] The working principle of this invention is as follows: When the flue gas flows vertically upward in the denitrification flue, it passes through the streamlined guide plates distributed circumferentially around the outer pipe. Due to the pressure difference between the windward and leeward sides of the airfoil structure of the guide plates, the axial kinetic energy of the flue gas is converted into a tangential rotational torque, driving the outer pipe to rotate around the inner pipe. Simultaneously, the ammonia-air mixture is transported through the inner pipe (fixed delivery channel) to a spherical nozzle that rotates synchronously with the outer pipe. The mixture is ejected from the inclined nozzle holes, forming a spiral jet, resulting in a diffusion angle of 60°~120° for the ammonia-air mixture, creating a three-dimensional mixing flow field of "rotational diffusion + radial injection" within the flue. This mixing flow field breaks the laminar flow state of the flue gas, forcing ammonia molecules to react with NO in the flue gas. x Molecular collisions are thorough, ultimately achieving uniform mixing across the entire surface, laying the foundation for efficient subsequent SCR catalytic reactions. The entire process requires no external power source such as an electric motor, relying entirely on the kinetic energy of the flue gas. This not only saves energy but also adapts to flue gas velocity variations under full-load conditions, ensuring stable mixing performance.
[0025] The above description is only for explaining the preferred embodiments of this utility model and is not intended to limit this utility model in any way. Therefore, any modifications or changes made under the creative spirit of this utility model should still fall within the scope of protection intended by this utility model.
Claims
1. A flue gas denitrification ammonia injection mixing device, comprising a nested tube assembly, a flue gas driving assembly, a spherical ammonia injection assembly, and a rotary bearing assembly, characterized in that... The nested tube assembly includes an inner tube (1) and an outer tube (2), with the outer tube (2) sleeved on the outside of the inner tube (1); the flue gas drive assembly includes multiple guide plates (3) evenly distributed along the circumference of the outer tube (2); the spherical ammonia injection assembly includes a spherical nozzle (4) rigidly connected to the upper part of the outer tube (2), with 4 to 6 inclined spray holes (5) on the spherical nozzle (4).
2. The flue gas denitrification ammonia injection mixing device according to claim 1, characterized in that: The center lines of the inner tube (1), outer tube (2) and spherical nozzle (4) are located on the same vertical line. The inner tube (1) and outer tube (2) are connected and rotated through the bearing (6). The outer tube (2) and spherical nozzle (4) are rigidly connected and rotate synchronously.
3. The flue gas denitrification ammonia injection mixing device according to claim 1, characterized in that: The guide plates (3) are evenly distributed around the outer tube (2), with a quantity of 3 to 6. They are at an angle of 15° to 25° with the vertical flue gas flow direction and rotate in the same direction. The guide plates (3) are all rectangular blades, which convert the flue gas flow power into the rotation power of the device.
4. The flue gas denitrification ammonia injection mixing device according to claim 1, characterized in that: The spherical nozzle (4) has 4 to 6 inclined nozzles (5), the angle between the inclined nozzles (5) and the radial direction of the spherical nozzle (4) is 20° to 30°, and the diameter of the nozzles is 1.5 to 2 mm.